arch/x86/kernel/vsmp_64.c

   1 /*
   2  * vSMPowered(tm) systems specific initialization
   3  * Copyright (C) 2005 ScaleMP Inc.
   4  *
   5  * Use of this code is subject to the terms and conditions of the
   6  * GNU general public license version 2. See "COPYING" or
   7  * http://www.gnu.org/licenses/gpl.html
   8  *
   9  * Ravikiran Thirumalai <kiran@scalemp.com>,
  10  * Shai Fultheim <shai@scalemp.com>
  11  * Paravirt ops integration: Glauber de Oliveira Costa <gcosta@redhat.com>,
  12  *                           Ravikiran Thirumalai <kiran@scalemp.com>
  13  */
  14
  15 #include <linux/init.h>
  16 #include <linux/pci_ids.h>
  17 #include <linux/pci_regs.h>
  18 #include <asm/pci-direct.h>
  19 #include <asm/io.h>
  20 #include <asm/paravirt.h>
  21
  22 /*
  23  * Interrupt control on vSMPowered systems:
  24  * ~AC is a shadow of IF.  If IF is 'on' AC should be 'off'
  25  * and vice versa.
  26  */
  27
  28 static unsigned long vsmp_save_fl(void)
  29 {
  30         unsigned long flags = native_save_fl();
  31
  32         if (!(flags & X86_EFLAGS_IF) || (flags & X86_EFLAGS_AC))
  33                 flags &= ~X86_EFLAGS_IF;
  34         return flags;
  35 }
  36
  37 static void vsmp_restore_fl(unsigned long flags)
  38 {
  39         if (flags & X86_EFLAGS_IF)
  40                 flags &= ~X86_EFLAGS_AC;
  41         else
  42                 flags |= X86_EFLAGS_AC;
  43         native_restore_fl(flags);
  44 }
  45
  46 static void vsmp_irq_disable(void)
  47 {
  48         unsigned long flags = native_save_fl();
  49
  50         native_restore_fl((flags & ~X86_EFLAGS_IF) | X86_EFLAGS_AC);
  51 }
  52
  53 static void vsmp_irq_enable(void)
  54 {
  55         unsigned long flags = native_save_fl();
  56
  57         native_restore_fl((flags | X86_EFLAGS_IF) & (~X86_EFLAGS_AC));
  58 }
  59
  60 static unsigned __init vsmp_patch(u8 type, u16 clobbers, void *ibuf,
  61                                   unsigned long addr, unsigned len)
  62 {
  63         switch (type) {
  64         case PARAVIRT_PATCH(pv_irq_ops.irq_enable):
  65         case PARAVIRT_PATCH(pv_irq_ops.irq_disable):
  66         case PARAVIRT_PATCH(pv_irq_ops.save_fl):
  67         case PARAVIRT_PATCH(pv_irq_ops.restore_fl):
  68                 return paravirt_patch_default(type, clobbers, ibuf, addr, len);
  69         default:
  70                 return native_patch(type, clobbers, ibuf, addr, len);
  71         }
  72
  73 }
  74
  75 static int vsmp = -1;
  76
  77 int is_vsmp_box(void)
  78 {
  79         if (vsmp != -1)
  80                 return vsmp;
  81
  82         vsmp = 0;
  83         if (!early_pci_allowed())
  84                 return vsmp;
  85
  86         /* Check if we are running on a ScaleMP vSMP box */
  87         if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
  88              (PCI_VENDOR_ID_SCALEMP || (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
  89                 vsmp = 1;
  90
  91         return vsmp;
  92 }
  93
  94 void __init vsmp_init(void)
  95 {
  96         void *address;
  97         unsigned int cap, ctl, cfg;
  98
  99         if (!is_vsmp_box())
 100                 return;
 101
 102         if (!early_pci_allowed())
 103                 return;
 104
 105         /* If we are, use the distinguished irq functions */
 106         pv_irq_ops.irq_disable = vsmp_irq_disable;
 107         pv_irq_ops.irq_enable  = vsmp_irq_enable;
 108         pv_irq_ops.save_fl  = vsmp_save_fl;
 109         pv_irq_ops.restore_fl  = vsmp_restore_fl;
 110         pv_init_ops.patch = vsmp_patch;
 111
 112         /* set vSMP magic bits to indicate vSMP capable kernel */
 113         cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
 114         address = early_ioremap(cfg, 8);
 115         cap = readl(address);
 116         ctl = readl(address + 4);
 117         printk(KERN_INFO "vSMP CTL: capabilities:0x%08x  control:0x%08x\n",
 118                cap, ctl);
 119         if (cap & ctl & (1 << 4)) {
 120                 /* Turn on vSMP IRQ fastpath handling (see system.h) */
 121                 ctl &= ~(1 << 4);
 122                 writel(ctl, address + 4);
 123                 ctl = readl(address + 4);
 124                 printk(KERN_INFO "vSMP CTL: control set to:0x%08x\n", ctl);
 125         }
 126
 127         early_iounmap(address, 8);
 128         return;
 129 }